Datasheet

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General Description

The MAX3387E 3V powered TIA/EIA-232 and V.28/V.24

is a communications interface with low power require-

ments, high data-rate capabilities, and enhanced elec-

trostatic discharge (ESD) protection. The MAX3387E

has three receivers and three transmitters. All RS-232

inputs and outputs are protected to ±15kV using the

IEC 1000-4-2 Air-Gap Discharge method, ±8kV using

the IEC 1000-4-2 Contact Discharge method, and

±15kV using the Human Body Model.

A proprietary low-dropout transmitter output stage

enables true RS-232 performance from a +3.0V to

+5.5V supply with a dual charge pump. The charge

pump requires only four small 0.1µF capacitors for

operation from a +3.3V supply. The MAX3387E is capa-

ble of running at data rates up to 250kbps while main-

taining RS-232 compliant output levels.

The MAX3387E has a unique V

pin that allows interop-

eration in mixed-logic voltage systems. Both input and

output logic levels are pin programmable through the

pin. The MAX3387E is available in a space-saving

TSSOP package.

Applications

Subnotebook/Palmtop Computers

PDAs and PDA Cradles

Cell Phone Data Cables

Battery-Powered Equipment

Hand-Held Equipment

Peripherals

Features

♦ V

Pin for Compatibility with Mixed-Voltage

Systems

♦ ±15kV ESD Protection on Rx Inputs and Tx Outputs

♦ Low 300µA Supply Current

♦ Guaranteed 250kbps Data Rate

♦ 1µA AutoShutdown Plus™ with Receivers Active

♦ Meets TIA/EIA-232 Specifications Down to 3.0V

MAX3387E

3V, ±15kV ESD-Protected, AutoShutdown Plus

RS-232 Transceiver for PDAs and Cell Phones

_______________________________________________________________

Maxim Integrated Products

0.1μF

MAX3387E

R2OUT13

R1OUT14

R2IN

GND

RS-232

OUTPUTS

TTL/CMOS

INPUTS

T2IN

T1IN

C2-

C2+

C1-

C1+

R1IN

T2OUT

T1OUT

V-

V+

0.1μF

23 15

BYPASS

+3.3V

T3IN

T3OUT

RS-232

INPUTS

TTL/CMOS

OUTPUTS

0.1μF

R3OUT12

R3IN

FORCEOFF

INVALID

FORCEON

Typical Operating Circuit

19-1561; Rev 3; 6/10

Ordering Information

AutoShutdown Plus is a trademark of Maxim Integrated

Products, Inc.

PART

MAX3387ECUG+

MAX3387EEUG+

TEMP. RANGE

0°C to +70°C

-40°C to +85°C

PIN-PACKAGE

24 TSSOP

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim’s website at www.maxim-ic.com.

Denotes a lead(Pb)-free/RoHS-compliant package.

Summary of content (14 pages)

PAGE 1
9-1561; Rev 3; 6/10 3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones The MAX3387E 3V powered TIA/EIA-232 and V.28/V.24 is a communications interface with low power requirements, high data-rate capabilities, and enhanced electrostatic discharge (ESD) protection. The MAX3387E has three receivers and three transmitters.
PAGE 2
MAX3387E 3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +6V VL to GND...................................................-0.3V to (VCC + 0.3V) V+ to GND ................................................................-0.3V to +7V V- to GND .................................................................+0.3V to -7V V+ +⏐ V-⏐(Note 1) .............................
PAGE 3
V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones (VCC = VL = +3.0V to +5.5V; C1–C4 = 0.1µF, tested at +3.3V ±10%; C1 = 0.047µF, C2–C4 = 0.33µF, tested at +5.0V ±10%; TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = VL = +3.3V, TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN Input Hysteresis TYP MAX UNITS 7 kΩ 0.
PAGE 4
TIMING CHARACTERISTICS (VCC = VL = +3V to +5.5V; C1–C4 = 0.1µF, tested at +3.3V ±10%; C1 = 0.047µF, C2–C4 = 0.33µF, tested at +5.0V ±10%; TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = VL = +3.3V, TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN RL = 3kΩ, CL = 1000pF, one transmitter switching Maximum Data Rate tPHL Receiver Propagation Delay Transmitter Skew ⏐VT_OUT⏐ > +3.7V t t ⏐ PHL PLH⏐ (Note 2) Receiver Skew ⏐tPHL - tPLH⏐ VCC = +3.
PAGE 5
3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones TRANSMITTER OUTPUT VOLTAGE vs. DATA RATE SUPPLY CURRENT (mA) 0 LOAD = 3kΩ, ONE TRANSMITTER SWITCHING AT DATA RATE, OTHER TRANSMITTERS 250kbps AT 1/8 DATA RATE 50 LOAD = 3kΩ, 1000pF ONE TRANSMITTER SWITCHING AT DATA RATE, OTHER TRANSMITTERS AT 1/8 DATA RATE 2.5 -2.5 -5.0 MAX3387E-04 5.0 OUTPUT VOLTAGE (V) SUPPLY CURRENT vs. LOAD CAPACITANCE 60 MAX3387E-03 7.5 40 120kbps 30 20 20kbps 10 -7.
PAGE 6
3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones MAX3387E Pin Description 6 PIN NAME FUNCTION 1 C1+ 2 V+ +5.5V Supply Generated by the Charge Pump 3 C1- Negative Terminal of the Voltage-Doubler Charge-Pump Capacitor 4 C2+ Positive Terminal of the Inverting Charge-Pump Capacitor 5 C2- Negative Terminal of the Inverting Charge-Pump Capacitor Positive Terminal of the Voltage-Doubler Charge-Pump Capacitor 6 V- 7 T1IN -5.
PAGE 7
3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones Dual Charge-Pump Voltage Converter The MAX3387E’s internal power supply consists of a regulated dual charge pump that provides output voltages of +5.5V (doubling charge pump) and -5.5V (inverting charge pump), regardless of the input voltage (VCC) over a +3.0V to +5.5V range. The charge pumps operate in a discontinuous mode: if the output voltages are less than 5.
PAGE 8
T_IN R_IN EDGE DETECT TRANSMITTERS ENABLED, INVALID HIGH FORCEOFF S 30s TIMER EDGE DETECT +2.7V AUTOSHDN R FORCEON RECEIVER INPUT LEVELS MAX3387E 3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones INDETERMINATE +0.3V 0V AutoShutdown, TRANSMITTERS DISABLED, 1μA SUPPLY CURRENT, INVALID LOW -0.3V INDETERMINATE -2.7V TRANSMITTERS ENABLED, INVALID HIGH Figure 2c. AutoShutdown Plus Logic Figure 3a.
PAGE 9
3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones MAX3387E RECEIVER INPUTS INVALID } REGION TRANSMITTER INPUTS TRANSMITTER OUTPUTS INVALID OUTPUT VCC tINVL tINVH 0 tAUTOSHDN tAUTOSHDN tWU tWU V+ VCC 0 V- Figure 3b. AutoShutdown Plus/INVALID Timing Diagram ±15kV ESD Protection POWERMANAGEMENT UNIT MASTER SHDN LINE 0.1μF 1M FORCEOFF FORCEON MAX3387E Figure 4.
PAGE 10
MAX3387E 3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones Table 1.
PAGE 11
3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones HIGHVOLTAGE DC SOURCE Cs 150pF I 100% DISCHARGE RESISTANCE STORAGE CAPACITOR 90% DEVICE UNDER TEST I PEAK CHARGE-CURRENT LIMIT RESISTOR RD 330Ω MAX3387E RC 50M to 100M 10% Figure 6a. IEC 1000-4-2 ESD Test Model IEC 1000-4-2 The IEC 1000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically refer to ICs.
PAGE 12
MAX3387E 3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones Power-Supply Decoupling Operation Down to 2.7V In most circumstances, a 0.1µF bypass capacitor is adequate. In applications that are sensitive to power-supply noise, decouple VCC to ground with a capacitor of the same value as charge-pump capacitor C1. Connect bypass capacitors as close to the IC as possible. Transmitter outputs will meet TIA/EIA-562 levels of ±3.7V with supply voltages as low as +2.7V.
PAGE 13
3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones 5V/div T1OUT 5V/div 5V/div R1OUT VCC = 3.3V 2μs/div Figure 10. Loopback Test Results at 250kbps Typical PDA/Cell-Phone Application The MAX3387E is designed with PDA applications in mind. Two transmitters and two receivers handle standard full-duplex communication protocol, while an extra transmitter allows a ring indicator signal to alert the UART on the PC.
PAGE 14
MAX3387E 3V, ±15kV ESD-Protected, AutoShutdown Plus RS-232 Transceiver for PDAs and Cell Phones Revision History REVISION NUMBER REVISION DATE 3 6/10 DESCRIPTION PAGES CHANGED Added Note 2 to the Electrical Characteristics table 4 Changed the Chip Information section to say “PROCESS: BiCMOS” 13 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.